Sheriff's deputies were dispatched around 11:30 a.m. to a house on Naranja Way, where the deputies found the deer carcass, Sgt. Art Martinez said.
Drag marks in the front yard led deputies to believe the deer carcass had been dragged by whatever was eating the deer, Martinez said.
The California Department of Fish and Game was notified, but officials were unable to confirm whether a mountain lion had eaten the deer.
Animal tracks that appeared to be left by a bobcat were found in the area, and Martinez said the deer could have been attacked by a bobcat, coyote or mountain lion.
However, recent mountain lion sightings in the county led the sheriff's office to notify residents through SMC Alert, the county's emergency notification system.
"With the recent mountain lion sightings we thought it would be prudent to put out SMC Alert to residents in the area," Martinez said.
Residents who see a mountain lion are asked to call 911 immediately, he added.
"Call 911 and we'll send somebody out," Martinez said. "We're just trying to be cautious."